TABLE 5.

The top 5 cited COPD drugs-related studies that were published from 1980 to 2021 and the most cited papers in 2021.

No	Author	Cited frequency	Drug	Condition or disease	Conclusion
1	(Vogelmeier et al., 2011)	455	Tiotropium	Moderate-to-very-severe COPD	In patients with moderate-to-very-severe COPD, tiotropium is more effective than salmeterol in preventing exacerbations
2	(Wedzicha et al., 2013)	364	QVA149	COPD stages III-IV, and one or more moderate COPD exacerbation in the past year	The dual bronchodilator QVA149 was superior in preventing moderate to severe COPD exacerbations compared with glycopyrronium, with concomitant improvements in lung function and health status
3	(Vogelmeier et al., 2013)	238	QVA149	COPD stages II-III, without exacerbations in the previous year	Once-daily QVA149 provides significant, sustained, and clinically meaningful improvements in lung function versus twice-daily salmeterol-fluticasone, with significant symptomatic benefit
4	(Vestbo et al., 2016)	231	Corticosteroid, fluticasone furoate, and vilanterol	Moderate COPD and heightened cardiovascular risk	In patients with moderate COPD and heightened cardiovascular risk, treatment with fluticasone furoate and vilanterol did not affect mortality or cardiovascular outcomes, reduced exacerbations, and was well tolerated
5	(Singh et al., 2016)	216	Single-inhaler combination of an extra fine formulation of beclometasone dipropionate, formoterol fumarate, and glycopyrronium bromide (BDP/FF/GB)	COPD had post-bronchodilator FEV1 of lower than 50%, one or more moderate-to-severe COPD exacerbation in the previous 12 months, CAT ≥10, and a Baseline Dyspnea Index focal score of 10 or less	This paper provide evidence for the clinical benefits of stepping up patients with COPD from an inhaled corticosteroid/long-acting β2-agonist combination treatment to triple therapy using a single inhaler
6	(Izquierdo et al., 2021)	13	Clinical Management of COPD in a Real-World Setting	COPD	This study identifies the main features of an unselected COPD population and the major errors made in the management of the disease